Validating Epub

Thom* · 06-10-2015, 04:22 PM

The Sigil menu has an option to validate the file using FlightCrew. No such option is available in Calibre Editor. If (in Calibre Editor) I "Run the Bug" (i.e. Tools-Check Book) is that the same or comparable to validating with such as FlightCrew, or how do they compare?

Thanks

theducks · 06-10-2015, 04:57 PM

IMHO A bit better

It suggests some corrections which would be used if you were to use the full 'Try and correct all' (I belong to the Full-Auto-is undesired crowd. I do sometimes let it fix a category of issue.)

It also does not (falsely?) flag some issues that Flight crew does?

kovidgoyal · 06-10-2015, 11:16 PM

Check Book is designed to warn you of problems that might actually affect the working of your book on real world devices, unlike epubcheck and flight crew, which mostly perform useless schema validation.

Check Book also gives you detailed information on how to fix many errors and is smart enough to auto fix quite a few if you ask it to.

But note, that passing Check Book is absolutely no guarantee that your book will later also pass epubcheck.

Thom* · 06-11-2015, 11:03 AM

Thank you, that explanation is helpful. There are no guarantees in life, but we try just the same.

senhal · 07-08-2015, 02:32 AM

Why not including also epub-check validation?

Quote:

Originally Posted by kovidgoyal

Check Book is designed to warn you of problems that might actually affect the working of your book on real world devices, unlike epubcheck and flight crew, which mostly perform useless schema validation.

I'm not an expert, but I think that some of these errors could affect...

Code:

<p><p>text</p></p>

element "p" not allowed here

Code:

<p>text</p><img alt="img" src="img01.png" />
or
<i><p>text</p></i>
or
<p><div>text</div></p>

element "img"/"i"/"div" not allowed here

Code:

<p><font size="2">text</font></p>
or
.font{size:2}

element "font" not allowed anywhere

Code:

<navMap><navPoint id="num_1" playOrder="2">

assertion failed: the first playOrder value is not 1
assertion failed: playOrder sequence has gaps

Code:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

Irregular DOCTYPE

Code:

<package xmlns="http://www.idpf.org/2007/opf" unique-identifier="uuid-id" version="1.0">

Version not supported

Code:

<img src="img01.png" />

element "img" missing required attribute "alt"

Quote:

metadata without language or title

element "metadata" incomplete; missing required element

Code:

ncx:
<meta content="b" name="dtb:uid"/>
opf:
<dc:identifier opf:scheme="uuid" id="uuid_id">a</dc:identifier>

meta@dtb:uid content 'b' should conform to unique-identifier in content.opf: 'a'

Code:

<navPoint id="num_1" playOrder="1">
...
<navPoint id="num_2" playOrder="1">

identical playOrder values for navPoint/navTarget/pageTarget that do not refer to same target

Code:

preserveAspectRatio="yes"

value of attribute "preserveAspectRatio" is invalid

kovidgoyal · 07-08-2015, 03:43 AM

Not a single one of those will prevent the book from working on any decent epub reading software. They are all examples of the mostly useless schema validation checks I talked about previously. And run the autofix html tool in the editor to fix half the html related "errors" automatically.

What people often fail to grasp is that HTML parsing is now a robustly solved problem. Regardless of what mess you make of your HTML, all modern HTML renders will parse it with the same algorithm to give you the same final result. That algorithm is codified in the HTML 5 standard. Therefore, all you need to do is check your html against a single rendering engine and you are largely done. XHTML and it's accompanying schema checks are trying to solve a problem that no longer exists.

The problems that are very relevant today are deviations in different HTML renderers from what the standard specifies (and note I said renderer, not parser) or areas the standard does not cover. And epubcheck cannot help you with either of those, since, by its very nature it only checks against the standard.

About the only use I have ever found for epubcheck is to detect typos in code areas made during hand crafting an epub file. This can often point out mistakes that you would otherwise only detect by actually looking at the book in a renderer. Your last example, of preserveAspectRatio is one such case.

senhal · 07-08-2015, 04:17 AM

Thanks for your reply, everything's clear

06-10-2015, 04:22 PM	#1
Thom* The Fumbler Posts: 66 Karma: 10 Join Date: Jun 2015 Device: android 4.2/fbreader	Validating Epub The Sigil menu has an option to validate the file using FlightCrew. No such option is available in Calibre Editor. If (in Calibre Editor) I "Run the Bug" (i.e. Tools-Check Book) is that the same or comparable to validating with such as FlightCrew, or how do they compare? Thanks

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06-10-2015, 04:57 PM	#2
theducks Well trained by Cats Posts: 31,047 Karma: 60358908 Join Date: Aug 2009 Location: The Central Coast of California Device: Kobo Libra2,Kobo Aura2v1, K4NT(Fixed: New Bat.), Galaxy Tab A	IMHO A bit better It suggests some corrections which would be used if you were to use the full 'Try and correct all' (I belong to the Full-Auto-is undesired crowd. I do sometimes let it fix a category of issue.) It also does not (falsely?) flag some issues that Flight crew does?

06-10-2015, 11:16 PM	#3
kovidgoyal creator of calibre Posts: 45,342 Karma: 27182818 Join Date: Oct 2006 Location: Mumbai, India Device: Various	Check Book is designed to warn you of problems that might actually affect the working of your book on real world devices, unlike epubcheck and flight crew, which mostly perform useless schema validation. Check Book also gives you detailed information on how to fix many errors and is smart enough to auto fix quite a few if you ask it to. But note, that passing Check Book is absolutely no guarantee that your book will later also pass epubcheck.

06-11-2015, 11:03 AM	#4
Thom* The Fumbler Posts: 66 Karma: 10 Join Date: Jun 2015 Device: android 4.2/fbreader	Thank you, that explanation is helpful. There are no guarantees in life, but we try just the same.

07-08-2015, 03:43 AM	#6
kovidgoyal creator of calibre Posts: 45,342 Karma: 27182818 Join Date: Oct 2006 Location: Mumbai, India Device: Various	Not a single one of those will prevent the book from working on any decent epub reading software. They are all examples of the mostly useless schema validation checks I talked about previously. And run the autofix html tool in the editor to fix half the html related "errors" automatically. What people often fail to grasp is that HTML parsing is now a robustly solved problem. Regardless of what mess you make of your HTML, all modern HTML renders will parse it with the same algorithm to give you the same final result. That algorithm is codified in the HTML 5 standard. Therefore, all you need to do is check your html against a single rendering engine and you are largely done. XHTML and it's accompanying schema checks are trying to solve a problem that no longer exists. The problems that are very relevant today are deviations in different HTML renderers from what the standard specifies (and note I said renderer, not parser) or areas the standard does not cover. And epubcheck cannot help you with either of those, since, by its very nature it only checks against the standard. About the only use I have ever found for epubcheck is to detect typos in code areas made during hand crafting an epub file. This can often point out mistakes that you would otherwise only detect by actually looking at the book in a renderer. Your last example, of preserveAspectRatio is one such case.

07-08-2015, 04:17 AM	#7
senhal Connoisseur Posts: 82 Karma: 25684 Join Date: Sep 2014 Device: Kindle NT	Thanks for your reply, everything's clear

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